I have anxiety and get panic attacks, have been on paroxetine and clonazepam and have had severe weight gain? any medicines that don't cause that?

Bupropion: None of the antidepressants are free of possible weight gain, but you might try bupropion (wellbutrin) or fluoxetine (prozac).

Wt. gain: Some antidepressants have less wt. Gain potential such as Pristiq and viibryd (vilazodone hydrochloride). Discuss with your prescribing physician.

Yes: I would agree with dr dutka that other antidepressants may have less weight gain than paroxetine. It would be a great question for you doctor. While Prozac or another ssri would be a fairly easy transition, switching from Paxil to wellbutrin (bupropion) can be quite difficult (due to serotonin withdrawal and activation from wellbutrin (bupropion)). Also make sure your thyroid function has been recently checked.